I’ve assembled my K8086 and as soon as I plug the 12V the relay is triggered, even without the phone line attached. Then when the phone line rings nothing more happens with the relay.
I’ve checked my assembling for reversed polarity components and everything is good and according to instructions.
Also, when I connect the phone line alone or with the 12V the LED lit a little bit, then it’s brighter when the phone line ring.
Another post from years ago, and the answer was: Check for soldering problems and check R4, R3, T1, R5, C3, Make sure opto-coupler is correctly inserted
I have the same issue and have checked very carefully all soldering joints seem good. I have done soldering for over 40yrs… and while I need readers to se clearly up close… I think this all looks good… but I am not 100% sure of the IC directions, the Socket was clearly marked with a notch… but the IC only had a dot on one corner I assumed that was Pin1, I used Safety Wash and carefully cleaned and checked to ensure there is no cross over from one solder point to another…
Here are a few pics from before I cleaned the board today.
Thanks for help